1. Field of the Invention
The present invention relates to a method, system, and an article of manufacture for device selection.
2. Description of the Related Art
A host system may perform input/output (I/O) operations with respect to a storage library by performing I/O operations with a set of devices in the storage library. A library manager coupled to the storage library may manage the storage library and the devices in the storage library. In certain implementations, the storage library may be a tape library and the devices may be tape devices. For any tape device, the tape device may first be online, then the tape device may be allocated to a job, and then the tape device may be started to process the I/O related to the job.
For instance, IBM* 3494 and IBM 3495 tape libraries include a library manager component that may manage up to 256 tape devices within the tape library. The tape devices are grouped into subsystems, and each subsystem may include up to 16 devices. A tape library may include from 1 to 16 subsystems, for a maximum of 256 devices. *IBM is a trademark of International Business Machines Corp.
Besides the normal input/output (I/O) operations from the host to specific devices in the storage library for reading from the tape and writing on the tape, there is a need to issue commands that are referred to as library manager commands from the host to the library manager. For example, a library manager command from the host may request the library manager to return information on the inventory of a certain type of volumes in the tape library.
However, in certain implementations, there may be no direct communication path from the operating system on the host to the library manager. When there is no direct communication path from the host to the library manager, the library manager commands may be sent from the host to a tape device in the tape library, and the tape device then passes the library manager command to the library manager. Any tape device in the tape library may be used to pass the command. There is an need in the art for an implementation that selects an appropriate tape device for passing the library manager commands to the library manager.